The present invention relates to the microbial decontamination arts. It finds particular application in conjunction with sporicidal decontamination of heating, ventilation, and cooling (HVAC) systems and will be described with particular reference thereto. However, it is to be appreciated that the present invention is also applicable to other types of microorganisms and to other decontamination applications.
HVAC systems typically include a series of delivery ducts, which deliver heated or cooled air from one or more heat exchangers to individual rooms or offices. The duct is typically largest in cross section adjacent the heat exchanger and diminishes in cross section as it branches to supply treated air to the individual rooms and offices. Typically, baffles at the register outlets and, in some systems, at various points along the ductwork system, control the relative amounts of air delivered to each room or register outlet. In modern construction, the baffles are sometimes motorized in order to provide individual room temperature control. The automated baffles are also used for safety, such as to shut down the supply of air if a fire is detected.
HVAC systems typically include a return system for returning air from the rooms to the heat exchanger. Some systems use a central return, which delivers return air from a central location to the heat exchanger to be retreated and recirculated. Other systems include a plenum, often defined by the open space above acoustic ceiling tiles, through which air is drawn back to the heat exchanger. Often, the plenums interconnect with ductwork, which conveys the return air back to the heat exchanger. Other systems include ductwork extending from a return register in each room. These individual ducts merge into progressively larger ducts as they approach the heat exchanger.
Blower motors and filters located adjacent the heat exchanger propel the treated air through the delivery duct system to the individual rooms and draw return air back to and through the heat exchanger. The ducts themselves are typically galvanized steel or aluminum. Portions of the ductwork or plenum may include acoustic material. In older buildings, the ductwork may have an accumulated layer of dust, dirt, and grease.
Large enclosures, such as rooms and buildings tend to become contaminated with a wide variety of microbial contaminants, including bacteria, molds, fungi, yeasts, and the like. These microorganisms thrive in damp spaces, such as behind walls, in plaster, under counters in bathrooms, and in ductwork and tend to be very difficult to eradicate. Some contaminants are brought into the room in the air, both through doorways, windows and the like as well as through ventilation systems. Contaminants are also carried into the room on the clothing or person by people using the room and from breathing. Some microbes cause a musty smell. Others can infect later users of the room. Additionally, there is a possibility that a room may be intentionally contaminated with pathogenic microorganisms, such as anthrax spores, smallpox virus, or the like. Some contaminants, such as tobacco smoke, body perfume, and medicinal odors are non-microbial.
When microbial contamination is introduced into a building, such as an Anthrax spore laced letter, the microbes tend to become airborne and are drawn into and pumped through the HVAC system. Killing spores and other microbes in the relatively inaccessible ductwork of the HVAC system has proven difficult.
The present invention provides a new and improved decontamination system and method which overcome the above-referenced problems, and others.